Semibatch reactor disadvantages

We focus mainly on the advantages and disadvantages of semibatch reactors. A semicontinuous reactor may be treated in many cases as either a batch reactor or a continuous reactor, depending on the overall kinetics and/or the phase of interest. 

Liquid-Phase Reactions. Semibateh reactors and CSTRs are used primarily for liquid-phase reactions. A semibatch reactor (Figure 1-15) has essentially Units the same disadvantages as the batch reactor. However, it has the advantages of... 

In this chapter, we first consider uses of batch reactors, and their advantages and disadvantages compared with continuous-flow reactors. After considering what the essential features of process design are, we then develop design or performance equations for both isothermal and nonisothermal operation. The latter requires the energy balance, in addition to the material balance. We continue with an example of optimal performance of a batch reactor, and conclude with a discussion of semibatch and semi-continuous operation. We restrict attention to simple systems, deferring treatment of complex systems to Chapter 18. 

Batch and Semibatch Polymerization. The reactor is normally operated in a semicontinuous mode by delaying vinyl acetate, solvent, and initiator. The same reactor can be used for stripping the poly(vinyl acetate) solution, provided that careful addition of methanol is used in order to prevent the viscosity in the reactor from becoming excessive (249). The disadvantages of batch polymerization are lack of product consistency and unsatisfactory economics in large scale production (250,251). The true batch reaction, where all the reactants are added to the reactor at time zero, yields a product having a very broad molecular weight distribution of limited commercial value. 

---